After 24 Years, Suddenly Left All Alone

By ADRIANE QUINLAN and MATT FLEGENHEIMER

Published: June 7, 2011

Do bears feel grief?

On Friday, workers at the Central Park Zoo euthanized one of its most popular and beloved residents: Ida, a 25-year-old polar bear who had suffered from liver disease. It was a painful moment for her keepers, who were given time with her before she was put down.

But Ida also left behind Gus, her companion for 24 years. Now, Gus, the zoo's only other polar bear, is alone.

The worry is how Gus, also 25, will respond. In 1994, when he would seemingly swim lap after endless lap without stopping, zookeepers believed he suffered depression. They brought in a therapist, who introduced toys and games and got Gus to cut back on his swimming.

But now will Gus mourn?

Bears do not mate for life, but they are fairly social, according to Dr. David Shepherdson, a scientist at the Oregon Zoo in Portland who has studied bear behavior extensively. ''For any animal that forms a close bond with another one, there would be some sense of loss.''

A Central Park Zoo official said Gus's behavior would be monitored in coming days.

''We haven't decided what we're going to do next as far as Gus goes,'' said Dr. Robert Cook, a top official at the Wildlife Conservation Society, which operates the zoo. ''But he seems to be fine.''

Dr. Cook, who was Ida's first veterinarian at the zoo, said, ''We really have to see how this goes.''

Three days after zookeepers performed a four-hour necropsy - or animal autopsy - on Ida's remains, Gus held court in the space they used to share. With sticks, toys and other playthings untouched, he spent Monday morning swimming between two rock structures, eyes peering out of the shallow waters as he drifted. Though a trainer viewed the activity as a positive step - he had rested quietly atop the rocks for much of the weekend - young zoo-goers struggled to become interested in a one-bear show.

''He looks bored,'' one child remarked.

''Could he kill people?'' asked another.

''Where are the monkeys?'' demanded a third, stomping out of the polar bear viewing area.

As for Ida's remains, the plans were to cremate them once tissue samples have been extracted for research purposes.

Referring to what can be learned about the species, Dr. Cook said, ''We consider when an animal dies in our collections that it's a unique opportunity.''

Some visitors also recognized an opportunity to use Ida's death to teach their children about mortality. Marie Claire Noel, who says she visits the zoo regularly with her 4-year-old granddaughter Camille Munoz, spent the weekend preparing for the inevitable question: Where's the other bear?

''Maybe it is an opportunity for her,'' said Ms. Noel, 65, who lives within walking distance of the park. ''You tell them what happens when they see a newborn penguin, right? This is just the other end of the cycle.''

This is a more complete version of the story than the one that appeared in print.

PHOTO: On Monday, three days after his companion was euthanized, Gus, a polar bear, swam in his habitat at the Central Park Zoo. (PHOTOGRAPH BY HIROKO MASUIKE/THE NEW YORK TIMES)